sociolab:

Sociology                     44.0
Ethnic Studies              16.3
Performing Arts             16.0
Neurosciences              13.1
Languages & Literature  11.9
Psychiatry                    11.8
History                         10.9
Biology                         10.7
Anthropology                 10.5
Art                                 8.8
Psychology                    8.0

Thus in 39 out of 42 disciplines, the D:R ratio is greater than 1. Of note, the psychology D:R was 8.0 (see the bolded row in the list immediately above). Not surprisingly, psychologists are quite liberal in their political views but not nearly as much as sociologists!

Click through to see the full list.  The numbers are listed as rations.